In this work, we present a new system for the determination of dissolved carbon dioxide (from 7.2 ppm to 425,6 ppm) in aqueous environments. Microfluidic technology has been incorporated in sensor design to reduce the volume of samples and reagents. Moreover, a detection system has been integrated in the chip, consisting of a white light -emitting diode as a light source and a high -resolution digital colour sensor as the detector, which are able to detect changes in colour produced by the reaction of the sensing chemistry and carbon dioxide in water. The optimised parameters found for the system are: flow rate 0.6 mL center dot min(-1), integration time 30 s and the time for pumping of solutions was 3 min, obtaining a LOD of 7.2 ppm. The CO2 response, reproducibility, precision, and stability of the sensing chemistry have been studied and compared with those obtained using bench-top instrumentation (i.e. a spectrophotometer), obtaining good agreement. (C) 2018 Elsevier B.V. All rights reserved.
co2 sensor; microfluidic system; water analysis; autonomous monitoring; carbon dioxide